Page 64 - GRIHA Manual Volume III - Introduction to National Rating System
P. 64
Building and system design optimization 57
Lighting and ventilation, gives minimum wind speeds for areas where somewhat warmer conditions
are prevalent, such as in godowns and machine shops and work is of lighter intensity, and higher
temperatures can be tolerated without much discomfort.
Table 2 Desirable wind speeds (m/s) for thermal comfort conditions
Dry bulb Relative humidity (percentage)
temperature
o C 30 40 50 60 70 80 90
28 – – – – – – –
29 – – – – – 0.06 0.19
30 – – – 0.06 0.24 0.53 0.85
31 – 0.06 0.24 0.53 1.04 1.47 2.10
32 0.20 0.46 0.94 1.59 2.26 3.04 –
33 0.77 1.36 2.12 3.00 – – –
34 1.85 2.72 – – – – –
35 3.20 – – – – – –
Source: Table 9, Clause 5.2.3.1, NBC Part 8, Building services; Section 1, Lighting and ventilation
Table 3 Minimum Wind Speeds (m/s) for Just Acceptable Warm Conditions
Dry bulb Relative humidity (percentage)
temperature
o C 30 40 50 60 70 80 90
30 – – – – – – –
31 – – – – – 0.06 0.23
32 – – – 0.09 0.29 0.6 0.94
33 – 0.04 0.24 0.6 1.04 1.85 2.1
34 0.15 0.46 0.94 1.6 2.26 3.05 –
35 0.68 1.36 2.10 3.05 – – –
36 1.72 2.70 – – – – –
Source: Table 10, Clause 5.2.3.1, NBC Part 8, Building services; Section 1, Lighting and ventilation
Thermal comfort conditions for non-air-conditioned spaces, mentioned in GRIHA Criterion 14,
have been derived based on the above two tables. GRIHA Criterion 14 specifies that to achieve the
required thermal comfort conditions in non-air-conditioned spaces the temperature should be less
than 33 C and relative humidity should be less than 70%. These thermal comfort conditions should
0
be met for 90% of all occupied hours (in composite, hot & dry and moderate climates) and 60% of
all occupied hours (in warm & humid climates) in naturally ventilated non-air-conditioned buildings.
3. Energy-performance optimization of buildings
Energy performance of buildings should be optimized without compromising with the thermal
comfort conditions inside the spaces. There are several strategies that can be adopted for improving
the energy performance of the building, that is, for reducing the energy performance index (EPI) of
the building. Following section provides a detailed description of these strategies for non-AC and
AC spaces.
Lighting and ventilation, gives minimum wind speeds for areas where somewhat warmer conditions
are prevalent, such as in godowns and machine shops and work is of lighter intensity, and higher
temperatures can be tolerated without much discomfort.
Table 2 Desirable wind speeds (m/s) for thermal comfort conditions
Dry bulb Relative humidity (percentage)
temperature
o C 30 40 50 60 70 80 90
28 – – – – – – –
29 – – – – – 0.06 0.19
30 – – – 0.06 0.24 0.53 0.85
31 – 0.06 0.24 0.53 1.04 1.47 2.10
32 0.20 0.46 0.94 1.59 2.26 3.04 –
33 0.77 1.36 2.12 3.00 – – –
34 1.85 2.72 – – – – –
35 3.20 – – – – – –
Source: Table 9, Clause 5.2.3.1, NBC Part 8, Building services; Section 1, Lighting and ventilation
Table 3 Minimum Wind Speeds (m/s) for Just Acceptable Warm Conditions
Dry bulb Relative humidity (percentage)
temperature
o C 30 40 50 60 70 80 90
30 – – – – – – –
31 – – – – – 0.06 0.23
32 – – – 0.09 0.29 0.6 0.94
33 – 0.04 0.24 0.6 1.04 1.85 2.1
34 0.15 0.46 0.94 1.6 2.26 3.05 –
35 0.68 1.36 2.10 3.05 – – –
36 1.72 2.70 – – – – –
Source: Table 10, Clause 5.2.3.1, NBC Part 8, Building services; Section 1, Lighting and ventilation
Thermal comfort conditions for non-air-conditioned spaces, mentioned in GRIHA Criterion 14,
have been derived based on the above two tables. GRIHA Criterion 14 specifies that to achieve the
required thermal comfort conditions in non-air-conditioned spaces the temperature should be less
than 33 C and relative humidity should be less than 70%. These thermal comfort conditions should
0
be met for 90% of all occupied hours (in composite, hot & dry and moderate climates) and 60% of
all occupied hours (in warm & humid climates) in naturally ventilated non-air-conditioned buildings.
3. Energy-performance optimization of buildings
Energy performance of buildings should be optimized without compromising with the thermal
comfort conditions inside the spaces. There are several strategies that can be adopted for improving
the energy performance of the building, that is, for reducing the energy performance index (EPI) of
the building. Following section provides a detailed description of these strategies for non-AC and
AC spaces.
